Direct Electrocardiograms from the Human Heart in Situ. Comparison of Direct Leads with Precordial Leads

Abstract
The clinical value of multiple precordial leads has been proved abundantly and they are now used routinely in many electrocardiographic laboratories. The experimental background was based upon the correlation of precordial leads with direct leads in dogs. Direct leads from the surface of human hearts have rarely been reported. The present study is presented to add further justification to the use of precordial leads as "semidirect" leads in the human being.